The present invention relates to the instruments for performing endoscopic procedures, and more particularly, for a verres needle system for insufflating a body cavity prior to an endoscopic surgical procedure.
Prior to performing an endoscopic procedure in a body cavity, such as the abdomen, it is first necessary to insufflate the abdominal cavity in order to separate the abdominal wall from the internal organs in the cavity. This separation creates space within which a surgical procedure may be performed by the use of endoscopic instrument, such as laparoscopy instruments in the case of abdominal surgery. The insufflation technique is performed by inserting a verres needle into the abdominal cavity and injecting gas, preferably carbon dioxide gas, through the needle into the cavity to inflate the cavity and thus, separate the abdominal wall from the organs of the cavity. Trocars are then inserted through the abdominal wall which allow laparoscopic instruments to be inserted into the abdominal cavity without allowing the pressurized carbon dioxide gas to escape.
A problem inherent in performing this insufflation technique is that it is currently difficult to determine with a high degree of precision the location of the tip of the verres needle through which gas is injected into the abdomen. It is necessary to position the tip of the needle at a location between the abdominal wall and the organs of the abdominal cavity (or between the tissue wall and the organs of the body cavity, if the technique is being performed in an area other the abdomen).
Should the verres needle tip be positioned inadvertently within the tissue wall surrounding the body cavity, the insufflation procedure could not be performed. Alternately, should the tip of the verres needle be positioned in an organ, artery or the bowel, performing the insufflation technique would result in compressed gas being injected into the organ, artery or bowel, resulting in pain at a minimum, and severe injury or death of the subject at a maximum.
One present device for performing this insufflation technique is a verres needle which includes a hollow tube that slidably receives an obturator within it. The hollow tube has a sharpened, open distal end from which the tip of the obturator protrudes. The obturator itself is a hollow tube having a side opening adjacent its distal end through which compressed gas is injected into the body cavity of the subject. The proximal end of the obturator includes a colored, and large tip which is visible through the clear plastic of the verres needle handle which supports both the obturator and tube. The enlarged tip is displaceable within a chamber within the plastic handle and is spring biased to urge the obturator toward a distal position with respect to the handle.
When such a verres needle is inserted into the subject, the resistance of the tissue wall forces the blunt end of the obturator rearwardly toward the proximal end of the tube, which exposes the sharpened end of the tube to effect its penetration through the tissue wall. Once the distal end of the tube clears the tissue wall, the resistance to further needle penetration caused by the tissue wall is reduced, which allows the spring to urge the obturator forwardly toward the distal end of the tube, resulting in a visibly perceptible displacement of the colored, enlarged end of the obturator within the handle. This displacement indicates that the tip of the needle has cleared the tissue wall surrounding the body cavity.
However, such a displacement could also occur if the needle tip had inadvertently entered the bowel, a soft tissue internal organ, or an artery, resulting in a false indication that the needle tip was properly positioned within the body cavity. Accordingly, there is a need to provide a verres needle system in which the positioning of the needle tip can be determined with a high degree of accuracy. Further, such a verres needle system preferably should be relatively inexpensive, to afford disposability, and simple to use.